What is the correct phraseology to request a parallel track due to weather for example?

Something like:

OE-DLM, request parallel track to the east, 2 nm

Background: I am asking for non-airline operations under IFR. I am using the GTN 750 and there is a feature to easily create a parallel track with a specified distance to the original route and I would like to use this feature. For example, when I'm in cruise flight, I see a weather cell and want to fly next to it by offsetting my route.


It is rather simple:

OE-DLM, request 2NM right of track.

However, weather circumnavigation is mostly done with headings. This way it is easier for the controller to predict your movement and thus preferred by many:

OE-DLM, request heading 120 for the next 20NM to avoid (weather).

This way it is easy for the controller to predict your movement and he has an idea where your avoidance will be completed. Additionally you are not forced to turn behind a cell you weren’t able to look behind before.

Mainly done in oceanic airspace where you try to make your way through the ITCZ (InnerTropical Convergence Zone) is this variant:

OE-DLM, request up to 20NM right of track to avoid (weather).

If approved you got a 20NM wide corridor to play in.

Flying offset is rather uncommon in the crowded European airspace (or generally every crowded airspace) but a normal thing everywhere else. China even uses it as a tactical separation method employed by the controller.


This is more often handled as heading changes than specific distances, you would do something like this:

Pilot: "XYZ Center, N12345 with request"
ATC: "N12345, XYZ Center go ahead"
Pilot: "XYZ Center, N12345 Requesting heading change 20 degrees right for weather"
ATC: "N12345 heading change approved"

And then after you've cleared your weather, you would request your revised heading in the same manner. If you need to descend/climb you can make those requests in a similar way, ATC may "block off" some altitude for you.

Usually though commercial flights will have routed you around already probably before taking off, so I assume you are talking about something other than airline operations.

  • $\begingroup$ Airline operations don't have any magic tio avoid weather. The ever changing nature of weather means dispatchers can do their best to route airliners around weather, but pilot requests for routing around weather is very common. $\endgroup$ – TomMcW Jun 10 '18 at 20:44
  • $\begingroup$ Thank you, I have edited my question to add background. $\endgroup$ – Noah Krasser Jun 10 '18 at 20:45
  • $\begingroup$ @TomMcW No, they don't, and I agree that it is common, but at least with airliners on known routes, one or two at "the front" request the routing and ATC reroutes the others in the air. The ones on the ground are rerouted before they take off by the company to avoid holds and get the slot times right on arrival. $\endgroup$ – Ron Beyer Jun 10 '18 at 21:01

enter image description here
(ICAO Doc 4444)

So if the pilot is the initiator of the request, it'll be something like this:

- Control, Stack 1, request
Stack 1, pass your message
- Stack 1 requesting parallel offset 5 NM left of route for weather

enter image description here
(YouTube) Above shows a 5 NM offset used to fly parallel to weather (no ATC in the video though).

It's also mentioned in the FAA AIM, albeit for wake turbulence:

enter image description here

  • $\begingroup$ The guidelines you quote are for "Wake Turbulence Encounters", it should work for weather as well, but wouldn't be the first place I would look for that, also the OP is asking for "non airline" operations, this may be different for IFR vs VFR. For VFR (other than in terminal control areas) I just have to let them know what I'm doing, for IFR it would be a request. If I'm tooling around VFR without flight following, I don't have to tell anybody... $\endgroup$ – Ron Beyer Jun 10 '18 at 21:06
  • $\begingroup$ @RonBeyer - The FAA bit was a bonus. Noah didn't say which jurisdiction, so ICAO seemed like the right place to look, Doc 4444 is not just for airline ops. $\endgroup$ – ymb1 Jun 10 '18 at 21:19
  • $\begingroup$ @TomMcW - It's not airway dependent, rather aircraft capability and for the ATC to ok it, which normally they should. $\endgroup$ – ymb1 Jun 10 '18 at 21:21
  • $\begingroup$ @ymb1 The OP is from Austria, but I suspect this is about simulator operations, so I think the OP should clarify the airspace as well, the FAA AIM/Doc may not be relevant at all. $\endgroup$ – Ron Beyer Jun 10 '18 at 21:21

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